//create new xls file
string file = "C:\\newdoc.xls";
Workbook workbook = new Workbook();
Worksheet worksheet = new Worksheet("First Sheet");
worksheet.Cells[0, 1] = new Cell((short)1);
worksheet.Cells[2, 0] = new Cell(9999999);
worksheet.Cells[3, 3] = new Cell((decimal)3.45);
worksheet.Cells[2, 2] = new Cell("Text string");
worksheet.Cells[2, 4] = new Cell("Second string");
worksheet.Cells[4, 0] = new Cell(32764.5, "#,##0.00");
worksheet.Cells[5, 1] = new Cell(DateTime.Now, @"YYYY\-MM\-DD");
worksheet.Cells.ColumnWidth[0, 1] = 3000;
workbook.Worksheets.Add(worksheet);
workbook.Save(file);

// open xls file
Workbook book = Workbook.Load(file);
Worksheet sheet = book.Worksheets[0];

 // traverse cells
 foreach (Pair<Pair<int, int>, Cell> cell in sheet.Cells)
 {
     dgvCells[cell.Left.Right, cell.Left.Left].Value = cell.Right.Value;
 }

 // traverse rows by Index
 for (int rowIndex = sheet.Cells.FirstRowIndex; 
        rowIndex <= sheet.Cells.LastRowIndex; rowIndex++)
 {
     Row row = sheet.Cells.GetRow(rowIndex);
     for (int colIndex = row.FirstColIndex; 
        colIndex <= row.LastColIndex; colIndex++)
     {
         Cell cell = row.GetCell(colIndex);
         // accessing pictures in cells
         Image image = worksheet.Pictures[new Pair<int, int>(rowIndex, colIndex)].Image;
     }
 }